The constitutionality of bounties has never been squarely passed upon by the Supreme Court. Their validity was questioned in

47 178 U. S. 130; 20 Sup. Ct. Rep. 775; 44 L. ed. 1000.

48The court say: "Whether the United States, in the exercise of the power of taxation, can be estopped by a contract that such power shall not be exercised, we need not consider, because the contract in this case does not, as we view it, mean that a State may not, or the United States may not, tax inheritances and legacies, regardless of the character of the property of which they are composed. That some of the holders of United States bonds may not have paid franchise taxes to the States, and others may have paid state or federal inheritance and legacy taxes, has nothing to do with the contract between the United States and the bondholders. The United States will have complied with their contract when they pay to the original holders of their bonds, or to their assigns, the interest, when due, in full, and the principal, when due, in full."

49 195 U. S. 27; 24 Sup. Ct. Rep. 760; 49 L. ed. 78.

50 For a summary of the arguments pro and contra as to the constitutionality of protective tariffs, see passim Stanwood, Tariff Controversies in the United States in the Nineteenth Century.

51 For the definition of bounties see Downs v. United States, 187 U. S. 496; 23 Sup. Ct. Rep. 222; 47 L. ed. 275.

Field v. Clark52 and United States v. Realty Co.,53 but in neither case did the court find itself obliged to decide the point. The ground upon which the constitutionality of bounties has been contested has been that their payment amounts to an appropriation of public moneys primarily for a private purpose. The courts have often held that an expenditure in the public interest is not invalidated by the fact that incidentally private interests are advanced thereby; but in general they have been held that an appropriation primarily and directly for the furtherance of private interests is not valfdated by the fact that incidentally public, interests are in a measure promoted.54